JR G770T with S3153

[GizmoB73]

Does anyone know if it is ok to use the G770T in digital mode with the Futaba S3153 servo?

The manual suggests only JR digital and JR gyro exclusive servos are OK but that sounds like JR trying to promote JR servos only.

I suspect it will be OK as the 3153 is quite quick, can anyone confirm or deny, my assumption.

Cheers

Gary.

[richieclarkie]

Of course JR will recommend their own servos . However I used a 9650 with mine and it was fine.

I see no reason for you to have a problem. You would cause damage to your servo if you plugged in an analogue servo with the 770T set to digital though.

However you may need to play about with different horn lengths if you find the tail bouncy or wagging.

[GizmoB73]

Of course JR will recommend their own servos . However I used a 9650 with mine and it was fine.

I see no reason for you to have a problem. You would cause damage to your servo if you plugged in an analogue servo with the 770T set to digital though.

However you may need to play about with different horn lengths if you find the tail bouncy or wagging.

Well, I just tried it and it did wag. I wound the gyro gain down to 55 which was about as low as I could go and it still wagged.

I will take your advice and try to reduce the mechanical gain by dropping the ball in a hole on the servo horn.

btw have you got any idea why the instructions suggest setting the L & R Travel Adjust to 150? I tried it at 150 and 100 and couldn't tell the difference while it was wagging?

Thanks

Gary.

[richieclarkie]

btw have you got any idea why the instructions suggest setting the L & R Travel Adjust to 150? I tried it at 150 and 100 and couldn't tell the difference while it was wagging?

Here's some advice from HELINUTZ taken from Rimryder. Hope it helps:

I use 150% left and right on the RUDDER channel atv's ( and dont change them)Use max on other radios like 125% futaba?

I use 100% on the gain channel atv's and dont change them. (unless you use the atv's to set your gain and not a gyro dedicated screen)

Set your limits mechanically so you are using about 70 to 80% of the range of the limit pot on the gyro. Move control balls to suit as required. On my evo 50 I had to move the tail ball in one hole as I didn't have a big enough wheel or an arm servo that sat perfectly at 90 degrees at the servo end

Standard stuff. 0 trim, 0 subtrim, servo direction and gyro sense direction.

In this present state without the gyro screen activated it will be asking for 100% gain so dont give up here.....the servo will be going nuts if you turn it on.

Set up your dual rates to suit the piro rate you want for the various idle up modes. I started with 70%

Set up 50% expo softer in the mid of course for all idle ups.

Activate the gyro screen and set 64%. Thats a great starting point.

This should help with any stops overshooting the mark and the nose turning back 10 or so degrees, settle the servo down and desensitise in the centre stick position. I asked about the brutal stops and he smiled and said "you rearn to be more gentle with your fingers when stopping"
Let the stick spring back to centre on this one and it stops....dead....so just adjust your expo and slow your stops down manually.

[GizmoB73]

Thanks Richie.

Looks like I do need to keep the rudder ATV's at 150 and need to get the gain ATV back to 100. I think I will then move the servo horn back out so that I can get full movement on the tail pitch slider.

Hopefully I might get a chance to do it today...

I did notice the brutal stops already, you get some interesting wind chop noises from the tail blades as they strain hard to stop the tail dead. I quite like that but I guess it isn't too kind on the tail.

Cheers

Gary

[SRH990]

I'm running a 770 gyro on my 600N although with an 8900g servo. This gyro is unlike any other I've ever owned, mainly CSM & Futaba. Initially I had to run the gain (using the gear channel and travel adjust, not gyro menu) at 28% which was a shock as I was usually used to around 70% but any more and it wagged like crazy. It still held rock solid though so I stuck with it, then I fitted a QUick UK tail and was able to increase gain to 38%. The gyro is very unforgiving of any binding in the tail pitch system, the stock 600N tail blade grips have problems with the thrust races binding and the Quick UK upgrade is much better. I'd check the tail linkage with the servo disconnected and see if its all smooth, if it is and you need to run a low gain to stop the wag then I'd say thats just how it is.

[cambs flyer]

Hope it all goes well mate, if in an hour maybe (18:03) now, if you fancy a test fly on the island I'm up for it.

I've been making adjustments with the 450 after checking the feathering shaft which is dead true after me getting cocky in the garden and finally busting one of those indestructible 325's, she went out in style and never altered anything else, once I checked everything over.

A noble death for a blade that has served so well, now a fresh pair of 325's are on her, she doesn't fly with quite the precision Mike managed to achieve on Thursday, but compared to my old Gyro shes fantastic to fly even only being 95% there.

Give me a call if you up for it bud'.

[GizmoB73]

Hope it all goes well mate, if in an hour maybe (18:03) now, if you fancy a test fly on the island I'm up for it.

I've been making adjustments with the 450 after checking the feathering shaft which is dead true after me getting cocky in the garden and finally busting one of those indestructible 325's, she went out in style and never altered anything else, once I checked everything over.

A noble death for a blade that has served so well, now a fresh pair of 325's are on her, she doesn't fly with quite the precision Mike managed to achieve on Thursday, but compared to my old Gyro shes fantastic to fly even only being 95% there.

Give me a call if you up for it bud'.

Hi Wayne,

I'll have to take a rain check on that tonight. The wife and baby both seem to have a bug and have both gone to bed early. I am on standby if the baby kicks off! I guess I'll have to settle for a bit of a tweak and a quick test fly in the garden now.

Cheers

Gary.

[cambs flyer]

Sorry to hear that Gary, I hope there better before long, I'm going over there in a bit just to try and iron out a few things with more space on hand.

Best to your fam' catch you later mate.

[GizmoB73]

Update:

Sorry to drag up an old thread, I have been away on holiday but I have had some success so thought I would post and update.

Well, at 18:00 this evening I eventually got a chance to have a look at my heli. Changed my physical gain back to the centre hole on the servo horn and reset the Gain ATV to 100% as it had been on 60%. A little bit of tweaking on the gyro gain setting (now set to 63%) and it now holds pretty darn well. Certainly better than my original gyro and doesn't continually drift. I don't have to play with the trim either.

I did find that above 63% gain, even though there was no hunting in a normal hover, sharp stabs of rudder would cause some scary tail end oscillations.

I guess I will continue tweaking things to make it even better if possible but for now, I am just really happy that it flies better than before. Thanks for everyone's help and input.

Gary.

[richieclarkie]

Good to see you have sorted it.

It's a very good gyro if a little fussy.